Systems and apparatus for providing motor protection in a power tool and method of manufacturing the same

ABSTRACT

Systems and apparatus for reliably sealing a surgical device are disclosed herein. Specifically, a surgical device including a drive shaft tube that is coupled to a drive shaft is disclosed. Because the drive shaft tube is coupled to the drive shaft, the drive shaft tube rotates at the same rotational speed as the drive shaft, which is less than the rotational speed of a cannulated motor shaft. The drive shaft tube can extend through the cannulated motor shaft. In addition, a sealing member can be provided to seal between the drive shaft tube (which rotates slowly) and the motor instead of between the motor shaft (which rotates more quickly) and the motor. The sealing member can be provided in a gap defined between an outer surface of a portion of the drive shaft tube extending beyond the cannulated motor shaft and the motor.

BACKGROUND

Reliable sealing of power tools used in a medical environment (i.e.,surgical power tools) is critical. For example, reliable sealing isnecessary to ensure sterility of the power tools. In particular, liquidssuch as bodily fluids must be prevented from leaking into the internalcomponents of the power tools to prevent contaminating patients.Additionally, reliable sealing is necessary to ensure reliability of thepower tools. During sterilization in an autoclave, the power tools areexposed to high temperatures and pressures. Thus, reliable sealing isneeded to prevent moisture from leaking into the internal components ofthe power tools to prevent damage, especially to electrical components.

There are various drive configurations for power tools used in a medicalenvironment. In some configurations, the power tools have in-line motorand drive shafts. In other words, the motor and drive shafts share acommon rotation axis. This is shown in FIG. 4, where the motor 402drives a motor shaft 406, which is communicatively connected to thedrive shaft 408 through a gear box device 404. As shown in FIG. 4, themotor shaft 406 and the drive shaft 408 share a common rotation axis401. In addition, the power tools are often required to accommodateK-wires, which are typically longer than the power tools themselves.Accordingly, the motor and drive shafts are cannulated or have hollowchannels to accommodate the K-wires.

In order to prevent fluid from leaking into the internal components(such as the motor 402), the power tools are provided with lip seals412A and 412B between the motor shaft 406 and the stator. The lip seals412A and 412B are provided at opposite ends of the motor shaft 406.Additionally, because the motor shaft 406 and the drive shaft 408 rotateat different rotational speeds, a gap is provided between the motorshaft 406 and the drive shaft 408. The lip seal 412B prevents fluid fromleaking into the gap.

It is difficult to provide reliable sealing in the power tools whenproviding lip seals against the motor shaft. In particular, the motorshaft is typically configured to rotate at high speeds (>15,000 RPM, forexample) in order to provide the desired output power. The reliabilityand sealing performance of lip seals, however, depends on thecircumferential speed of the motor shaft. Accordingly, the reliabilityof the lip seals is degraded at higher speeds. Additionally, power lossincreases over-proportionally with the circumferential speed of themotor shaft. Thus, reliable sealing of power tools is needed.

SUMMARY

Systems and apparatus for providing motor protection in a power tool aredisclosed herein. The systems and apparatus can be used to reliably seala surgical device. Specifically, a surgical device including a driveshaft tube that is coupled to a drive shaft is disclosed. Because thedrive shaft tube is coupled to the drive shaft, the drive shaft tuberotates at the same rotational speed as the drive shaft, which is lessthan the rotational speed of a cannulated motor shaft. The drive shafttube can extend through the cannulated motor shaft. In addition, asealing member can be provided to seal between the drive shaft tube(which rotates more slowly) and the motor instead of between the motorshaft (which rotates more quickly) and the motor. For example, thesealing member can be provided in a gap defined between an outer surfaceof a portion of the drive shaft tube extending beyond the cannulatedmotor shaft and the motor housing.

For example, a surgical device according to one implementation of theinvention can include: a motor having a cannulated motor shaft; a gearbox device; a drive shaft; a drive shaft tube and a sealing member. Thedrive shaft can be communicatively connected to the cannulated motorshaft through the gear box device. The drive shaft can extend distallyfrom the gear box device and the cannulated motor shaft can extenddistally to the gear box device. In addition, the cannulated motor shaftand the drive shaft can have a common rotation axis. Additionally, thedrive shaft tube can be coupled to the drive shaft and extend proximallyfrom the gear box device through the cannulated motor shaft and beyondthe proximal end of the cannulated motor shaft. The sealing member canbe arranged adjacent to the proximal end of the cannulated motor shaftand provide a seal between the drive shaft tube and the motor.

Optionally, the surgical device can include a support member arrangedadjacent to the proximal end of the cannulated motor shaft. The driveshaft tube can be mounted on the support member such that a space isprovided between the drive shaft tube and the cannulated motor shaft.For example, the support member can be a ball bearing.

In some implementations, the gear box device can be configured toconvert a higher rotational speed of the cannulated motor shaft to alower rotational speed of the drive shaft.

Additionally, the drive shaft tube can be coupled to the drive shaftsuch that the drive shaft tube is configured to rotate at the lowerrotational speed of the drive shaft. Alternatively, the drive shaft tubeand the drive shaft can be formed from a single piece of material suchthat the drive shaft tube is configured to rotate at the lowerrotational speed of the drive shaft.

In addition, at least a portion of the sealing member can contact anouter surface of the drive shaft tube. For example, the sealing membercan include a concentric ring and a lip. The lip can extend radiallyfrom the concentric ring, the concentric ring can be disposed around anouter surface of the drive shaft tube, and at least a portion of the lipcan contact the outer surface of the drive shaft tube.

In some implementations, the surgical device can include a motor housingsupporting the motor. A gap can be provided between an inner surface ofa proximal portion of the motor housing and the outer surface of thedrive shaft tube, and at least one of the sealing member and the supportmember can be disposed in the gap.

In another implementation, a sealing system for use with a surgicaldevice can include: an elongate drive shaft tube coupled to a driveshaft that extends through a cannulated motor shaft; and a sealingmember disposed in contact with at least a portion of the elongate driveshaft tube. In addition, the elongate drive shaft tube can be configuredto rotate at a rotational speed of the drive shaft.

Optionally, the cannulated motor shaft can have proximal and distalends, at least a portion of the elongate drive shaft tube can extendbeyond the proximal end of the cannulated motor shaft, and the sealingmember can be disposed in contact with the portion of the elongate driveshaft tube extending beyond the proximal end of the cannulated motorshaft.

In some implementations, the rotational speed of the drive shaft can beless than or equal to approximately 3,000 RPM.

Additionally, the elongate drive shaft tube can be integrally coupled tothe drive shaft.

Alternatively or additionally, the elongate drive shaft tube and thedrive shaft can be formed from a single piece of material.

For example, the sealing member can include a concentric ring and a lip.The lip can extend radially from the concentric ring, the concentricring can be disposed around an outer surface of the drive shaft tube,and at least a portion of the lip can contact the outer surface of thedrive shaft tube.

In yet another implementation, a method of manufacturing a surgicaldevice can include: providing a motor comprising a cannulated motorshaft; providing a gear box device; providing a drive shaft; andproviding a sealing member. The drive shaft can be communicativelyconnected to the cannulated motor shaft through the gear box device. Thedrive shaft can extend distally from the gear box device and thecannulated motor shaft can extend distally to the gear box device. Inaddition, the cannulated motor shaft and the drive shaft can have acommon rotation axis. Additionally, the drive shaft tube can be coupledto the drive shaft and extend proximally from the gear box devicethrough the cannulated motor shaft and beyond the proximal end of thecannulated motor shaft. The sealing member can be arranged adjacent tothe proximal end of the cannulated motor shaft and provide a sealbetween the drive shaft tube and the motor.

The method can also include providing a support member adjacent to theproximal end of the cannulated motor shaft. The drive shaft tube can bemounted on the support member such that a space is provided between thedrive shaft tube and the cannulated motor shaft.

In some implementations, the gear box device can be configured toconvert a higher rotational speed of the cannulated motor shaft to alower rotational speed of the drive shaft.

In addition, at least a portion of the sealing member can contact anouter surface of the drive shaft tube. For example, the sealing membercan include a concentric ring and a lip. The lip can extend radiallyfrom the concentric ring, the concentric ring can be disposed around anouter surface of the drive shaft tube, and at least a portion of the lipcan contact the outer surface of the drive shaft tube.

In some implementations, the method can include providing a motorhousing supporting the motor. A gap can be provided between an innersurface of a proximal portion of the motor housing and the outer surfaceof the drive shaft tube, and at least one of the sealing member and thesupport member can be disposed in the gap.

Other systems, methods, features and/or advantages will be or may becomeapparent to one with skill in the art upon examination of the followingdrawings and detailed description. It is intended that all suchadditional systems, methods, features and/or advantages be includedwithin this description and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the drawings are not necessarily to scale relative toeach other. Like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 illustrates a cross-sectional view of a surgical device;

FIG. 2 illustrates another cross-sectional view of the surgical device;

FIG. 3A illustrates a cross-sectional view of a proximal portion of thesurgical device of FIGS. 1 and 2;

FIG. 3B illustrates a cross-sectional view of the proximal portion ofthe surgical device along line I-I′ of FIG. 3A; and

FIG. 4 illustrates a cross-sectional view of a motor shaft in a surgicaldevice in related art.

DETAILED DESCRIPTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art. Methods and materials similar or equivalent to those describedherein can be used in the practice or testing of the present disclosure.While implementations will be described for providing a reliable seal ina surgical power tool, it will become evident to those skilled in theart that the implementations are not limited thereto but may also beapplicable to other types of power tools.

Referring now to FIGS. 1 and 2, cross sectional views of a surgicaldevice 100 are shown. The surgical device 100 is a power tool usedduring various surgical procedures. The surgical device 100 has aproximal end 105 and a distal end 103, and the surgical device 100 has adevice casing 118 that houses the internal components. The surgicaldevice 100 includes a motor 102. The motor 102 includes a motor housing116 supporting the motor 102 and an elongate motor shaft 106. The motorhousing 116 is stationary, and the motor shaft 106 is capable ofrotating. As shown in FIGS. 1 and 2, a proximal portion of the motorhousing 116 accommodates an end piece 150. The end piece 150 holds thedevice casing 118 in place. For example, the end piece 150 can bescrewed into the motor housing 116. In the implementations discussedherein, the motor 102 can be any type of electric motor operable todrive surgical tools. It should be understood that the characteristicsof the motor 102 can be selected based on the desired operatingcharacteristics of the surgical device 100. One or more surgical toolattachments such as surgical drills, saws, etc., for example, can beattached to the surgical device 100 through the coupling head 130. Insome implementations, the coupling head 130 can accommodate additionaldrive attachments that accommodate the surgical tools. For example, theadditional drive attachments can convert/transfer motive force to thesurgical tools. In addition, the surgical device 100 is operable todrive K-wires. In particular, a K-wire attachment that accommodatesK-wires can be attached to the surgical device 100 through the couplinghead 130. As shown in FIG. 2, an operator can grip the surgical device100 by the handle 120 and operate the motor 102 using triggers 122. Forexample, one of the triggers 122 can cause the motor 102 to rotate in afirst direction (i.e., a forward direction) and another one of thetriggers 122 can cause the motor 102 to rotate in a second direction(i.e., a backward direction).

The motor 102 includes the elongate motor shaft 106, which iscommunicatively connected to an elongate drive shaft 108 through a gearbox device 104. As shown in FIGS. 1 and 2, the motor shaft 106 extendsdistally through the motor 102 to the gear box device 104. The gear boxdevice 104 is configured to convert and transfer the rotational speedand torque of the motor shaft 106 to the drive shaft 108. Typically, amotor suitable for use in a surgical power tool is required to berelatively small and lightweight. It should be understood that smaller,lighter and more powerful motors require higher speeds. Therefore, themotor 102 rotates at a higher rotational speed than the desiredrotational speed of the attachable surgical tools in order to achievethe desired output torque, and the gear box device 104 can be used toconvert and transfer the rotational speed and torque of the motor shaft106 to the drive shaft 108. For example, in some implementations, themotor shaft 106 may rotate at approximately 15,000 to 20,000 RPM whilethe desired rotational speed of the drive shaft 108 may be approximately3,000 RPM (i.e., 5-6 times slower than the motor shaft 106).Alternatively or additionally, the additional drive attachments canfurther reduce the rotational speed to the desired rotational speed ofthe surgical tools, which may be approximately less than or equal to1,000 RPM. Further, the additional drive attachments can increase therotational speed to the desired rotational speed of the surgical tools(e.g., 15,000 RPM), which may be approximately greater than therotational speed of the drive shaft 108, to drive high-speed cuttingtools such as burrs, for example. It should be understood that therotational speeds discussed above for the motor 102, motor shaft 106,drive shaft 108, surgical tools, etc. can be selected based on thedesired operating characteristics of the surgical device 100, andtherefore, can have other values. For example, the desired rotationalspeed of the drive shaft 108 can be more or less than 3,000 RPMdepending on the desired operating characteristics of the surgicaldevice 100. Thus, the desired rotational speed of the drive shaft 108 isnot limited to 3,000 RPM, which is only one example desired rotationalspeed.

The gear box device 104 can be any type of gear box that is capable ofconverting and transferring the rotational speed and torque of the motor102 in one or more steps. For example, the gear box device 104 can be aplanetary gear system. For example, the motor shaft 106 can be connectedto a sun gear 104A, and the drive shaft 108 can be connected to one ormore planetary gears 104B. In some implementations, the drive shaft 108can be connected with the one or more planetary gears 104B using pin(s)104C that are pushed through the drive shaft 108 and into one of theplanetary gears 104B. Alternatively, the drive shaft 108 can beconnected with the one or more planetary gears 104B using pins 104C thatare integral with the drive shaft 108. The gear box device 104,therefore, converts a higher rotational speed of the motor shaft 106 toa lower rotational speed of the drive shaft 108. Additionally, the gearbox device 104 transfers torque from the motor shaft 106 to the driveshaft 108. In some implementations, a lower torque of the motor shaft106 is converted to a higher torque and transferred to the drive shaft108.

As shown in FIGS. 1 and 2, the motor shaft 106 and the drive shaft 108are in-line. Additionally, the motor shaft 106 extends distally throughthe motor 102 to the gear box device 104, and the drive shaft 108extends distally from the gear box device 104. In the implementationsdiscussed herein, the motor shaft 106 and the drive shaft 108 arecoaxial, or share a common rotation axis 101, for example. When themotor shaft 106 and the drive shaft 108 are coaxially, the surgicaldevice 100 can be made smaller as compared to the case where the motorshaft 106 and the drive shaft 108 do not share the common rotation axis101. Additionally, the motor shaft 106 and the drive shaft 108 can becannulated shafts. In other words, the motor shaft 106 and the driveshaft 108 can have hollow central channels extending through the lengthof each shaft. As discussed above, the surgical device 100 is operableto drive K-wires, which are typically longer than the surgical device100 itself. Accordingly, the K-wires can be inserted entirely throughthe surgical device 100 (i.e., from the distal end 103 to the proximalend 105), exiting through the device housing 118 of the surgical device100.

A drive shaft tube 110 can be coupled to the drive shaft 108. The driveshaft tube 110 can extend proximally from the gear box device 104. Forexample, the drive shaft tube 110 can extend proximally from the gearbox device 104 into the motor shaft 106. When the motor shaft 106 iscannulated, the drive shaft tube 110 can extend through the hollowchannel of the motor shaft 106. In particular, the drive shaft tube 110can extend through the motor shaft 106 and beyond a proximal end of themotor shaft 106. For example, a portion of the drive shaft tube 110 canextend proximally beyond the proximal end of the motor shaft 106. Asshown in FIGS. 1 and 2, the drive shaft tube 110 extends proximally fromthe gear box device 104 through an entire length of the motor shaft 106.Similarly to the motor shaft 106 and the drive shaft 108, the driveshaft tube 110 can be cannulated in order to accommodate insertion ofthe K-wires through the surgical device 100. In addition, the driveshaft tube 110 can share the common rotation axis 101 with the motorshaft 106 and the drive shaft 108.

The drive shaft tube 110 can be coupled to the drive shaft 108 such thatthe drive shaft tube 110 is capable of rotating at the same rotationalspeed as the drive shaft 108. In some implementations, the drive shafttube 110 and the drive shaft 108 are separate pieces that are integrallycoupled together, for example, in a location adjacent to the gear boxdevice 104. In other implementations, the drive shaft tube 110 and thedrive shaft 108 are a single, integrated piece (i.e., formed from asingle piece of material). In both cases discussed above, the driveshaft tube 110 and the drive shaft 108 are capable of rotating at thesame rotational speed. In particular, the drive shaft tube 110 iscapable of rotating at a lower rotational speed as compared to the motorshaft 106. In addition, the drive shaft tube 110 and the drive shaft 108are coupled such that there is no gap or space for fluid to leak fromthe hollow channel of the drive shaft tube 110 and/or the drive shaft108 to the motor 102. Optionally, a wall thickness of the drive shaft108 can be greater than a wall thickness of the drive shaft tube 110because torque is transferred from the motor shaft 106 to the driveshaft 108 while there is essentially no torque on the drive shaft tube110.

A sealing member 112 can be provided adjacent to the proximal end of themotor shaft 106 to prevent fluid from leaking into the motor 102. Insome implementations, the sealing member 112 can be provided between themotor housing 116 and the drive shaft tube 110. Alternatively, in otherimplementations, the sealing member 112 can be provided between the endpiece 150 and the drive shaft tube 110. Referring now to FIG. 3A, a gap124 is provided between the proximal portion of the motor housing 116,which is stationary, and the drive shaft tube 110, which is capable ofrotating. The gap 124 can be an annular ring surrounding the portion ofthe drive shaft tube 110 that extends beyond the proximal end of themotor shaft 106. Alternatively, the gap 124 can be a space having anyshape surrounding the portion of the drive shaft tube 110 that extendsbeyond the proximal end of the motor shaft 106. Specifically, the gap124 is provided between an inner surface 116A of the proximal portion ofthe motor housing 116 and an outer surface 110A of the drive shaft tube110. The gap 124 provides a clearance (or space) in which the driveshaft tube 110 can rotate. In order to prevent fluid from leakingthrough the gap 124, the sealing member 112 can be provided in the gap124. At least a portion of the sealing member 112 can contact the outersurface 110A of the drive shaft tube 110. The portion of the sealingmember 112 contacting the outer surface 110A of the drive shaft tube 110can extend circumferentially around the entire outer surface 110A of thedrive shaft tube 110. For example, the sealing member 112 can be a lipseal, an O-ring, or any other type of seal. The sealing member 112 canbe made from any type of material suitable for preventing fluid fromleaking into the motor 102 such as rubber (i.e., NBR, Silicone, etc.),for example.

The sealing member 112 can be provided around the outer surface 110A ofthe drive shaft tube 110. For example, referring to FIGS. 3A and 3B, thesealing member 112 can have a concentric ring 112A and a lip 112B. Thelip 112B can extend radially from the concentric ring 112A, and the lip112B can be tapered from the concentric ring 112A. By tapering the lip112B, the portion of the lip 112B contacting the outer surface 110A ofthe drive shaft tube 110 can be reduced. The concentric ring 112A can beprovided around the outer surface 110A of the drive shaft tube 110 suchthat at least a portion of the lip 112B contacts the outer surface 110Aof the drive shaft tube 110. The sealing member 112, therefore, preventsfluid from leaking into the motor 102.

In addition to the sealing member 112, a support member 114 can beprovided adjacent to the proximal end of the motor shaft 106. In someimplementations, the support member 114 can be provided between themotor housing 116 and the drive shaft tube 110. Alternatively, in otherimplementations, the support member 114 can be provided between the endpiece 150 and the drive shaft tube 110. For example, the support member114 can be provided in the gap 124, which is provided between theproximal portion of the motor housing 116 and the drive shaft tube 110,and can be disposed between the sealing member 112 and the proximal endof the motor shaft 106. The drive shaft tube 110 can be mounted throughthe support member 114. The support member 114 provides support for thedrive shaft tube 110 so that the drive shaft tube 110 does not contactthe motor shaft 106. As discussed above, the motor shaft 106 can rotateat a higher rotational speed than the drive shaft tube 110. Thus, thedrive shaft tube 110 and the motor shaft 106 should not come intocontact. As shown in FIG. 3A, a space 126 is provided between the driveshaft tube 110 and the motor shaft 106. Specifically, the space 126 isprovided between the outer surface 110A of the drive shaft tube 110 andan inner surface of the motor shaft 106. The space 126 can be, forexample, an annular ring that extends around the outer surface 110A ofthe drive shaft tube 110. The support member 114 can be configured tomaintain the space 126 between the drive shaft tube 110 and the motorshaft 106. In addition, the support member 114 allows the drive shafttube 110 to rotate within the support member 114. For example, thesupport member 114 can be a ball bearing.

Similarly to the sealing member 112 and the support member 114 discussedabove (and provided near the proximal end of the surgical device 100), adistal sealing member 132 and a distal support member 134 can beprovided near the distal end of the surgical device 100. For example, asshown in FIGS. 1 and 2, the distal sealing member 132 and the distalsupport member 134 can be provided adjacent to a distal end of the driveshaft 108. The distal sealing member 132 and the distal support member134 can be provided in a space between stationary components of thesurgical device 100 and the drive shaft 108, which can rotate. Thedistal support member 134, which can be a ball bearing, for example, canprovide support for the drive shaft 108 while allowing the drive shaft108 to rotate within the distal support member 134. In addition, thedistal sealing member 132, which can be a lip seal, for example, canprevent fluid from leaking between the drive shaft 108 and the motor102.

According to the implementations discussed herein, it is possible toprovide a more reliable sealing in a surgical device. For example, morereliable sealing is provided because the sealing member seals betweenthe drive shaft tube (which rotates more slowly) and the motor insteadof between the motor shaft (which rotates more quickly) and the motor.In addition, it is possible to reduce the number of sealing membersneeded to protect the motor of the surgical device because an additionalsealing member is not required to seal between the motor shaft and thedrive shaft. It is also possible to reduce drag moment on the motorbecause there is less friction present on the slower rotating (andhigher torque) drive shaft tube than on the faster rotating (and lowertorque) motor shaft. Further, by reducing the speed difference betweenthe K-wire and the drive shaft tube, it is possible to reduce noise andwear on both the K-wire and the rotating shaft.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

What is claimed:
 1. A surgical device, comprising: a motor comprising acannulated motor shaft, the cannulated motor shaft having proximal anddistal ends; a motor housing supporting the motor and the cannulatedmotor shaft; an end piece coupled to a proximal end of the motorhousing; a gear box device within the motor housing; a drive shaftcommunicatively connected to the cannulated motor shaft through the gearbox device, the drive shaft extending distally from the gear box deviceand the cannulated motor shaft extending distally to the gear boxdevice, wherein the cannulated motor shaft and the drive shaft have acommon rotation axis; a drive shaft tube coupled to the drive shaft thatextends proximally from the gear box device through the cannulated motorshaft and beyond the proximal end of the cannulated motor shaft, whereinthe drive shaft tube is coupled to the drive shaft such that the driveshaft tube rotates at a same rotational speed as the drive shaft; asealing member arranged adjacent to the proximal end of the cannulatedmotor shaft and between the motor housing and the drive shaft tube, thesealing member providing a seal between the drive shaft tube and themotor housing, wherein the sealing member comprises a concentric ringand a lip, the lip extending radially from the concentric ring, and theconcentric ring being disposed around an outer surface of the driveshaft tube, wherein the lip is tapered from the concentric ring to theouter surface of the drive shaft, and the tapered portion of the lipcontacts the outer surface of the drive shaft tube; and a support memberarranged adjacent to the proximal end of the cannulated motor shaft,wherein the drive shaft tube is mounted on the support member such thatthe support member provides a space between the drive shaft tube and thecannulated motor shaft.
 2. The surgical device of claim 1, wherein thesupport member is a ball bearing.
 3. The surgical device of claim ofclaim 1, wherein the gear box device is configured to convert a higherrotational speed of the cannulated motor shaft to a lower rotationalspeed of the drive shaft.
 4. The surgical device of claim 1, wherein atleast a portion of the sealing member contacts an outer surface of thedrive shaft tube.
 5. The surgical device of claim 4, wherein a gap isdefined between an inner surface of a proximal portion of the motorhousing and the outer surface of the drive shaft tube, and at least oneof the sealing member and the support member are disposed in the gap. 6.A sealing system for use with a surgical device, the surgical deviceincluding a motor, a motor housing supporting the motor and an end piececoupled to a proximal end of the motor housing, the motor having acannulated motor shaft communicatively connected to a drive shaftthrough a gear box device, the drive shaft extending distally from thegear box device and the cannulated motor shaft extending distally to thegear box device, the sealing system comprising: an elongate drive shafttube coupled to the drive shaft that extends through the cannulatedmotor shaft, wherein the drive shaft tube is coupled to the drive shaftsuch that the drive shaft tube rotates at a same rotational speed as thedrive shaft; a sealing member located between the motor housing and thedrive shaft tube, the sealing member disposed in contact with at least aportion of the elongate drive shaft tube, wherein the elongate driveshaft tube is configured to rotate at a rotational speed of the driveshaft, wherein the sealing member comprises a concentric ring and a lip,the lip extending radially from the concentric ring, and the concentricring being disposed around an outer surface of the drive shaft tube,wherein the lip is tapered from the concentric ring to the outer surfaceof the drive shaft, and the tapered portion of the lip contacts theouter surface of the drive shaft tube; and a support member arrangedadjacent to and abutting the proximal end of the cannulated motor shaft,wherein the drive shaft tube is mounted on the support member such thata space is provided along the entire length between the drive shaft tubeand the cannulated motor shaft.
 7. The sealing system of claim 6,wherein the cannulated motor shaft has proximal and distal ends, atleast a portion of the elongate drive shaft tube extends beyond theproximal end of the cannulated motor shaft, and the sealing member isdisposed in contact with the portion of the elongate drive shaft tubeextending beyond the proximal end of the cannulated motor shaft.
 8. Thesealing system of claim 6, wherein the rotational speed of the driveshaft is less than or equal to approximately 3,000 RPM.
 9. The sealingsystem of claim 6, wherein the elongate drive shaft tube is integrallycoupled to the drive shaft.
 10. The sealing system of claim 9, whereinthe elongate drive shaft tube and the drive shaft are formed from asingle piece of material.
 11. A method of manufacturing a surgicaldevice, comprising: providing a motor comprising a cannulated motorshaft, the cannulated motor shaft defining proximal and distal ends;providing a motor housing supporting the motor and the cannulated motorshaft; providing an end piece coupled to a proximal end of the motorhousing; providing a gear box device within the motor housing; providinga drive shaft communicatively connected to the cannulated motor shaftthrough the gear box device, the drive shaft extending distally from thegear box device and the cannulated motor shaft extending distally to thegear box device, wherein the cannulated motor shaft and the drive shafthave a common rotation axis; providing a drive shaft tube coupled to thedrive shaft that extends proximally from the gear box device through thecannulated motor shaft and beyond the proximal end of the cannulatedmotor shaft, wherein the drive shaft tube is coupled to the drive shaftsuch that the drive shaft tube rotates at a same rotational speed as thedrive shaft; providing a sealing member adjacent to the proximal end ofthe cannulated motor shaft and between the motor housing and the driveshaft tube, the sealing member providing a seal between the drive shafttube and the motor, wherein the sealing member comprises a concentricring and a lip, the lip extending radially from the concentric ring, andthe concentric ring being disposed around an outer surface of the driveshaft tube, wherein the lip is tapered from the concentric ring to theouter surface of the drive shaft, and the tapered portion of the lipcontacts the outer surface of the drive shaft tube; and a support memberarranged adjacent to the proximal end of the cannulated motor shaft,wherein the drive shaft tube is mounted on the support member such thata space is provided along the entire length between the drive shaft tubeand the cannulated motor shaft.
 12. The method of claim 11, wherein thegear box device is configured to convert a higher rotational speed ofthe cannulated motor shaft to a lower rotational speed of the driveshaft.
 13. The method of claim 11, wherein a gap is defined between aninner surface of a proximal portion of the motor housing and the outersurface of the drive shaft tube, and at least one of the sealing memberand the support member are disposed in the gap.